PORTLAND, Maine — It’s a sure sign of spring: bicycle riders, from kids wobbling on their first two-wheelers to Spandex-clad athletes on high-tech racing machines, once again occupy city streets.

This year, several initiatives are making Portland a more bike-friendly place for cyclists.

But some wonder if it is becoming too friendly.

In February, the city was one of five communities in the country to receive federal assistance for creating a bike-sharing program, which would offer the public free or low-cost access to a shared pool of bicycles for short trips. A forum to gather public input on the idea is scheduled at 5:30 p.m. Wednesday, May 8, in City Hall.

And Portland has begun creating a network of “neighborhood byways” — secondary streets with traffic-calming signs, medians and other infrastructure designed to create safer, more enjoyable routes for cyclists and pedestrians.

The network, recently piloted with five miles of byways in Deering Center, could someday stretch for 29 miles throughout the city, according to Bruce Hyman, Portland’s bicycle and pedestrian coordinator.

No wonder that local cyclists — and even the city’s website — tout Portland as a great place to ride.

But with the city welcoming more and more cyclists, some people wonder if there will be more problems on the road. Indeed, other cities may already be experiencing more accidents and road rage as they become more bike-friendly.

In New York City, which has added nearly 300 miles of bike lanes since 2002 and started bike-sharing last year, concerns about added traffic have led neighborhood groups to oppose some of the new bike-friendly measures. And the city’s comptroller released a report claiming that the bike-sharing program would lead to more accidents, injuries and potential lawsuits.

In Boston, an accident that killed a cyclist prompted the Boston Globe to publish an editorial in February about increasing hostility toward bicycle riders.

“Sharing the road with increasing numbers of cyclists can be frustrating for drivers. But disregard for the safety of cyclists has reached pathological levels among some drivers,” the Globe opined.

In Portland, there is little evidence of increasing dangers or road rage. Still, accidents happen.

From 2005 through 2010, there were 208 collisions reported between cyclists and motorists, Hyman said, an average of about 35 a year. In 2012, there were 56 accidents involving cyclists, according to information obtained from police.

And many cyclists report scary near-misses.

“I was riding here today and a driver blew past me, honking his horn and screaming something out the window,” said Chris Sawtelle of Portland, as she left the Great Maine Bike Swap at the University of Southern Maine on April 28. “I guess I was moving too slow for him. He nearly side-swiped me.”

Motorists have said that cyclists can be a safety hazard, too. That worry prompted former state Rep. Ralph Sarty, R-Denmark, to introduce a bill in the Legislature two years ago that would have placed a 2 percent tax on bike sales, with the proceeds used to build new bike lanes.

“In recent years, recreational bicycling has put thousands of new bikes on our highways, increasing the potential for accidents,” Sarty wrote in 2011. “The current laws regarding bicycle use on public ways place little if any responsibility or liability on the bicyclists. Almost all the responsibility and liability is on motorists.”

The legislation was killed, but concerns about sharing the road remain.

Jim Tasse, education director for the Bicycle Coalition of Maine, noted cyclists are allowed to ride on all Maine roads, except interstate highways and a portion of U.S. Route 1 between Brunswick and Bath.

“Motorists should expect cyclists to be on the roads, and they have every right to be there,” he said.

Motorists must leave at least 3 feet between their vehicles and cyclists, according to state law, and are allowed to drive in the opposite lane when necessary to safely pass a cyclist.

Cyclists, for their part, must obey the same traffic rules as motorists, and must ride as far to the right as “practicable.” But the law also allows them to ride two abreast, and to ride in a road’s travel lane when making a left turn or to avoid a vehicle or safety hazard.

Tasse acknowledged that it’s easy to get frustrated when driving behind a slower-moving cyclist or a large group of riders that is difficult to pass.

“But the conflicts often arise because [a motorist] feels a need for speed,” he said, noting that drivers should obey the speed limit and be patient.

Most of all, he said, motorists and cyclists should “exercise some restraint and courtesy” and realize the dangers a two-ton vehicle poses, regardless of who is at fault.

“When cars and bikes get too close,” he said, “it’s like juggling a loaded gun.”